What specific system did you start with?

I used to read my brother-in-law's old AD&D books for hours, pouring over the Complete Book of X and wowing at the illustrations and wondering what in tarnation THAC0 was. The first dungeon crawler I played back in the day was almost certainly Heroquest, the old board game with the barbarian and the mini furniture and the Gargoyle. The first proper roleplaying game I ever rolled dice for, however, was D&D 3.0. I can starkly remember trying out a Cleric, deciding that Summon Monster I was too complicated, and having him trip down a crevasse so I could reroll a Fighter instead.

I grew up being told it was evil, and only for devil worshippers, if you can believe that. So, I grew up without D&D, but I read Forgotten Realms and Dragonlance all the time since I was 8 years old. One day, I found out the two were related when I was in my early 20s and started rethinking everything that I was told growing up. But it didn't matter, because I didn't know anyone who played. It wasn't until years later that I found out some of my coworkers were looking for a place to host their D&D sessions. I told them if they'd teach me to play, I'd provide the house, the food, the snacks, and the liquor. Once I learned, I started running games. I still host games from time to time, but now everyone else pitches in for food and drinks. I offer XP bonuses for coming in costume or bringing a sick soundtrack to go with the day's session.

I tried 4E... it didn't take. I've played and DM'd a bit of 5E, but I keep coming back home to 3.5 for some reason. I just love that edition.

Special nod to @Raveled for giving love to HeroQuest. I played it as a teenager, and later Advanced HeroQuest in my 30s. Did you know OG Hero Quest is a collectors item now? It's worth a lot of money if you have one in tact. Now I regret giving it to one of my old roommates when I moved out. I wouldn't have thought it counted as a system... but It was an awesome, and really underrated game.

My first exposure to D&D was in a hotel room when I was a kid. A couple of other kids were talking about Monks and levels and my visual was of monkeys on scaffolding. Ha, what a newb!

Later, me and my friend started playing D&D. It was probably 1E like Tattered King above. From there I dabbled in Top Secret, Star Frontiers, Gamma World and even a lot of the Palladium products (Robotech, TMNT, Rifts, Recon). RPG's didnt have the same level of acceptance then as they do now. You young whipper snappers dont know how good ya got it!!!

I'm probably a bit of an odd ball in this, but first actual game ever was Mage: The Ascension. Not sure what version, but this was back in 2001, so maybe Revised?

True story, I've never actually played a game of D&D. While I was certainly interested, my regular group just tended to stick with the White Wolf stuff through the years. I'm familiar with D20 mechanics, having eventually played Pathfinder and Star Wars Saga Edition. I do currently own the 5E Player's Handbook, so maybe I'll be able to remedy that in the near future.

Honestly? It's more common than you'd think. Especially in non-English speaking countries the markets can be dominated by other RPGs. For example, in Germany The Dark Eye is basically the roleplaying game, to which D&D is a sidenote. In Poland Warhammer Fantasy is a big deal. France as far as I know has its own line of French RPGs, only some of which are translated. Let alone a country like Japan.

I basically only play PbP. It means I don't have to keep to a particular schedule, and I don't have to talk to actual people directly. If I play anything similar with friends in person it's more board games.

Special nod to @Raveled for giving love to HeroQuest. I played it as a teenager, and later Advanced HeroQuest in my 30s. Did you know OG Hero Quest is a collectors item now? It's worth a lot of money if you have one in tact. Now I regret giving it to one of my old roommates when I moved out. I wouldn't have thought it counted as a system... but It was an awesome, and really underrated game.

Apparently there's still an active scene for it, to the point where someone made a random adventure generator for the thing. Imagine still playing that barbarian after 30 years, ehn?